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Wednesday, October 16, 2019
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data M at Lake Königssee

COPRA® RF makes ecology contribution at Lake Königssee

Its name is world-famous and conjures up images of emerald-green water in the midst of a unique landscape – Lake Königssee.

Glide across the lake in silent electric-powered boats, listen to the impressive Königssee echo. Germany’s cleanest lake is also called the “gem” of the Berchtesgaden National Park.

This oasis was endangered. Because the energy to the inn at St. Bartholomä was primarily oil-based, which could only be transported across by ship.

With an increasing number of visitors – as many as 7000 a day – and the resulting greater energy consumption, it gradually became too risky to ship oil across he lake. So it was decided to fit St. Bartholomä with a new power supply.

A power cable was laid hrough Lake Königssee to the St. Bartholomä peninsula.

Production, transport and laying of the cable for this unusual activity were handled by the Hannover company NEXANS, a customer of data M and user of COPRA® RF software, which consequently made an essential contribution to conserving the environment at Lake Königssee.

The special cable was first positioned on top of the lake by floating car tires, before being sunk to a depth of up to 190 m. NEXANS can also lay such cables on the high seas.

For a number of years now NEXANS has used COPRA® RF softwareto develop the roll forming tools for manufacture of the cable sheaths.

Which is how the world-famous Lake Königssee echo sounded as far as us.

COPRA® RF in composite pipe manufacture

THE Thomas Machines S.A. / Switzerland, Couvet

1. Company portrait
The Swiss company THE Thomas Machines S.A. has existed since 1986, starting as Thomas Electronique S.A. to develop and manufacture custom electronics applications in machine engineering. The company was reincorporated under the present name in October 2002 when it extended its activities to the development and building of complete machines and installations. Today THE, sited close to Neuchâtel, employs some 25 personsand a staff of freelancers to create machines and installations for the manufacture of:

  • composite pipes
  • other roll formed pipes
  • irrigation pipes

The company’s portfolio also includes:

  • automatic sorting and assembly machines
  • custom controllers (e.g. water treatment, electroplating)

2. What is a composite pipe?
Composite pipe is the name given to multilayer pipes used primarily in domestic installations.

Composite pipes usually consist of the following materials:

  • an inner pipe of cross-linked polyethylene of high sealing quality
  • an inner layer of hot melt adhesive
  • an aluminum metal pipe, WIG or laser welded
  • an outer layer of hot melt adhesive
  • an outer polyethylene pipe of high sealing quality

The nominal widths of the pipes are between 14 and 110 mm; the aluminum pipe has a layer thickness of 0.1 to 1.5 mm. Such composite pipes are used both for underfloor heating and drinking water/process water installations. The purposes of the aluminum pipe, produced by roll forming and lengthwise welding, in the described material composition are as follows:

  • creation of gas-tightness
  • ensuring simple forming in installation (bending by hand in the lower diameter range, retaining form once bent)
  • use of press fittings

3. Production of aluminum pipe
The following apparatus, all supplied by THE, is needed to produce the aluminum layer of the composite pipe:

  • 1 strip decoiler or
  • 2 strip decoilers*
  • Slewing pillar crane with vacuum manipulator for strip rolls
  • Dancer
  • Cross-welding machine (WIG or laser)*
  • Strip server*
  • Longitudinal cutting device for strip finishing
  • Edge strip shredder
  • Capstan to apply tractive force to strip
  • Roll forming tool with fast-change device
  • WIG or laser welding unit
  • Seam tracking system for laser welding
  • Compacting machine

*: For continuous production across the end of a strip roll

Production of the aluminum pipe, especially the roll forming and lengthwise welding step, is subject to strict quality demands:

  • The thin wall of the strip (typically 0.2 to 0.5 mm) calls for a very sensitive forming process.
  • Welding without an extra material requires a welding gap of approaching 0 mm (especially laser welding with a beam diameter of 0.2 to 0.3 mm), i.e. horizontally the as yet unwelded strip sides must be opposite one another and almost tolerance-free.
  • The permissible vertical toler ance is likewise very restricted: a difference in height between the unwelded strip sides of only 0.1 mm reduces the seam cross-section of a 0.2 mm strip to 50%. That is of course inadmissible.
  • The composite pipe manufacturer must guarantee at least 50 years service life for the entire pipe.

These demands are met by the following measures:

  • Processing of quality strip
  • Easy strip guidance with the aim of creating minimal extra residual stress
  • Inline finishing of the strip by longitudinal cutting
  • Controlled inline elongation of the strip with the aim of reducing existent inhomogeneity
  • Form and configuration of the forming rolls optimized by COPRA® RF
  • Forming bench = precision tool
  • Seam tracking system - the laser beam follows possible angular motion of the welding gap

4. Roll forming tool
THE offers a forming bench optimized for each of the dimensions covered by item 2. Here it is able to rely on the solid expertise of its personnel, cquired and already proven in many more than 100 applications. This expertise encompasses the use of COPRA® RF, the design of roll forming tools, the application of WIG and/or laser welding systems, as well as upstream and downstream processes of overall composite pipe manufacture.
In each of these applications COPRA® RF has demonstrated its reliability as a tool that is decisive in optimizing the forming process – through the implanted skills, the modularity of the software and its ease of use.
Difficult cases in what could be called the border region of the computing model on which the Deformation Technology Module FTM is based are supported and solved with competent assistance from data M Software + Engineering GmbH – also with the aid of nonlinear finite element simulation in the form of COPRA® FEA RF.

THE roll forming tools are assurance of an extremely stable forming process with minimal reforming thanks to their application specific and highly precise construction, simulation of the forming process and careful manufacture and assembly. A maximum of the elongation of the aluminum appearing just once in the service life of the pipe is during installation and use. The manufacturing speed (e.g. 35 m min for D16 x 0.24-Al) is not restricted by the roll forming / lengthwise welding but by the other processes of composite pipe manufacture.

A specialty of THE roll forming tools is the absence of any setting possibility. Composite pipe manufacturers seldom have the expertise of a tube and profile manufacturer. In this case setting possibilities tend to be adjustment possibilities instead. For this reason and because of the clear selection of dimensions, for THE roll forming tools the rule is:
1 pipe dimension = 1 forming bench

So a change of dimension in the metal part of a composite pipe installation only takes 15 to 20 minutes before production can start again. THE also produces roll forming tools for other dimensions and for other than composite pipe manufacture – D5.4 x 0.15 roll forming tool for stainless steel and nickel alloys).

5. Other components for aluminum pipe production
WIG cross-welding, machine, or for laser welding, Strip server, Longitudinal cutting device, Compacting machine

6. Complete composite pipe manufacturing line
A composite pipe manufacturing line will usually consist of three lines one after the other:

  • Inner pipe with adhesive (can also be separate)
  • Metal pipe
  • Outer pipe with adhesive

Author: Attila Otto, freelancer of THE and owner of OTTO engineering